Although households that use tap water as drinking water is on a continual rise, places like small farming and fishing villages still use groundwater as drinking water.
But for farming and fishing villages that cannot have in place a water treatment plant due to the fact that a central water supply system like the supply system of the tap water is preferred, large groundwater storage tanks are installed in each village on high elevated areas, which store water pumped up from large tube wells. The groundwater storage tanks provide water to each household in a village.
In addition, a groundwater disinfection device that injects antiseptic solution such as hypochlorous acid water to the pumped up water to disinfect and sterilize it has been invented.
But the conventional groundwater disinfection device simply injects antiseptic solution to the pumped up groundwater in order to disinfect it. Because of this, the antiseptic solution does not get evenly distributed to the groundwater, and as a result its effectiveness is often below expectations. The conventional groundwater disinfection device does not supply oxygen but antiseptic solution.
There are many cases that considerable amount of radon is contained in the pumped up groundwater, often exceeding allowed limits.
Radon is a colorless, odorless, and tasteless inert gas and is one of the decay products of uranium (U-238). Also, Radon is one of radioisotopes with half-life of about 3.8 days. It is known to be one of the harmful substances to the body that emits alpha particles as it decays. Radon is carcinogenic to cause lung cancer when it enters the body through respiratory organs. If Radon enters through digestive organs, it is known to cause gastric cancer.
Therefore, when groundwater containing radon is used as drinking water, there is a high likelihood of gastric cancer being developed, and when it is used as household water, there is a high likelihood of lung cancer being developed by secondary contamination of indoor air. Especially, with regard to the harmful effects of radon to humans, development of lung cancer caused by breathing in radon in a gas state is known to be the greatest. According to data from U.S. EPA, it is the second leading cause of lung cancer, next to smoking.
Looking at regulations of major countries with regard to radon, the U.S. has it set to 4,000 pCi/L (guideline), Finland to 8,100 pCi/L (for drinking water), and Norway to 13,500 pCi/L (guideline). According to published findings of radon content in groundwater in South Korea, about 10% exceed the U.S. guideline, and groundwater of some regions contain radon in quantities that exceed appropriate levels for use as drinking water.
That is, under supervision of the Ministry of Environment since 1998, South Korea has been investigating the degree to which natural radioactive substances are contained in groundwater. According to survey results released in 2008 in which groundwater of water supplies in 523 villages across the country expected to contain a large amount of natural radioactive substances due to geological features were surveyed, 124 places exceeded the drinking water guideline set in the U.S. with regard to radon content. As a result, management with regard to this is planned to be stepped up.
In addition, the Ministry of Environment carried out a pilot operation of radon reduction facilities in village water supplies containing a large amount of radon (over 15,000 pCi/L) in which it confirmed the effects of aeration facilities and active charcoal and the possibility of management in reducing the degree of Radon (source: Ministry of Environment report released in February of 2009). This led to the invention of a radon reduction device by the inventors of KR Patent Application No. 10-2009-0068476.
But the device does not include an infection system for groundwater. Also, it has shortcomings in that it does not meet expectations in terms of reducing radon contained in groundwater and fails to acquire enough power to reduce radon in groundwater.